KR830001167B1 - Hydroformylation Method for Making n-Valer Aldehyde - Google Patents

Abstract

None.

Description

Hydroformylation Method for Making n-Valer Aldehyde

The accompanying drawings are schematic flow charts of butene hydroformylation plant.

The present invention relates to a hydroformylation process for the production of n-valeraldehyde with butene-1 in mixed C ₄ -olefin crude oil.

It is well known in the art to react olefins with hydrogen and carbon monoxide in the presence of a suitable catalyst to produce an aldehyde having at least one more carbon atom than the starting olefin.

Such reactions are referred to as "oxo" reactions, oxonation or hydroformylation. Such various reactions using modified catalysts to obtain alcohol as the main product rather than aldehyde are also known.

The simplest olefin, ethylene, produces a single aldehyde, or propionaldehyde, in hydroformylation, but propylene allows two aldehydes, n-and n, It is also possible to produce iso-butyr aldehydes. The proportion of n- and isobutyraldehyde formed is dependent on the reaction conditions used and the nature of the catalyst. In general, n-aldehydes are more economically desirable than the corresponding iso-products that are often combusted as fuel. The reason is that iso-products do not meet the demand as fuel. Two or more aldehydes may be produced with higher order terminal olefins such as hexene-1 or octene-1 because of the potential for isomerization of the molecule with the transfer of olefinic double bonds. Another byproduct in all hydroformation is the alkanes corresponding to the starting material olefins. It is formed by hydrogenation under reaction conditions.

In hydroformylation, an initial process uses a cobalt containing catalyst such as cobalt octacarbonyl. In general, however, the use of such catalysts has the disadvantage of working at extremely high pressures up to several hundred atmospheres. This is because product recovery is difficult and it is difficult to obtain n- / iso-product aldehydes of about 4: 1 or more.

Recently, rhodium contact hydroformylation methods have been developed for hydroformylation of terminal olefins. This method has also been practiced commercially. This method requires a low pressure of about 20 kg / cm ² or less, allows a single product recovery step, and has the advantage of producing n- / iso-product aldehydes at a high rate of 10: 1 or more. Have. This method is described, for example, in US Pat. No. 3,527,809 and UK Pat. No. 1,338,237 and involves the use of organo-Phosphorus ligands in addition to rhodium complexes. Other explanations of this method are described in a paper entitled "Low-pressure oxo process yields a better product mix" (Chemical Engineering, Dec. 5, 1977) and West German Patent Publication No. 2,715,685.

In the process described in US Pat. No. 3,527,809, the hydroformylation reaction with terminal olefins comprises (1) rhodium complex catalyst, (2) olefinic feed, (3) triorgano-phosphine ligand and its concentration , (4) relatively low temperature range, (5) relatively low total gas pressure, and (6) partial pressures generated by hydrogen and carbon monoxide. Typical types of active catalysts are hydridocarbonyltris (triphenylphosphine) rhodium (I) having the general formula HRh (CO) (PPh ₃ ) ₃ . An excess of triphenylphosphine is used with this kind of catalyst. Among the olefins mentioned above are butene-1 (see column 40 of column 4). However, no experiments with butene-1 using a rhodium catalyst are described in detail and although Example 77 is mentioned as using Boot-1-ene in Example 9, it is understood that Example 9 is oct-1- It is considered misprinted because it uses yen. Moreover, there is no indication of using the process as mixed olefins.

The development of this method is described in British Patent Specification No. 1,338,237. This includes the use of high boiling point liquid condensation products of the product alhydride as diluents, such as mixtures of trimers (III) and (IV) and tetramers (VIII), which are described on page 4 of the specification above. have. Among the olefins listed for use in this process are 1-butenes (see column 68, page 7, above). However, experimental procedures describing the use of 1-butene are not described in British Patent Specification No. 1,338,237. There is no indication of operating the process with mixed olefin feeds.

West German Patent No. 2,715,685 proposes hydroformylation of C ₂ -C ₅ α-olefins by a rhodium-contacting process, in which the volume of catalyst-containing liquid in the reactor is at the same rate as generating aldehydes. By regulating the gas through the furnace reactor, the high boiling aldehyde condensation products are removed at the same rate as they are formed. However, no experimental details of the process using butene-1 are described, in particular the olefins illustrated in the figures and in the single examples are propylene. Operation with a mixed olefin feed is not shown.

Ethylene and propylene are commercially available as virtually pure crude oils. Although large amounts of butylene are produced in petroleum refining, the separation of pure butene-1 from mixed C ₄ hydrocarbon streams is quite expensive. Typically such mixed C ₄ -olefin feedstreams contain, in addition to butene-1, cis- and trans-butene-2, iso-butylene, small amounts of n- and iso-butane, and trace amounts of propane and pentane. It is therefore economically interesting to use such a feedstream with butene-1 as the source without purification of butene-1.

Hydroformylation processes using mixed C ₄ -olefin feedstreams and cobalt catalysts are commercially operated in the United States. This process results in a mixture of n- and iso-valeraldehyde, and both butene-1 and butene-2 (cis- and trans-form) are converted to C ₅ aldehyde products. However, the n- / iso-aldehyde product ratio is only about 3: 1-4: 1. This process has all the drawbacks associated with the use of cobalt catalysts such as the difficulty of product recovery and the use of high reaction pressures. Another problem is that iso-butylene reacts with the product aldehyde under hydroformylation reaction conditions to form a resin, which further complicates the difficult process associated with the use of cobalt as a catalyst. In order to avoid such resin formation, it is necessary to remove iso-butylene from the C ₄ -olefin crude oil, for example, by an acid washing step. This adds to operating costs and energy required for the process.

Although the literature on commercial low pressure rhodium-contact hydroformylation focuses on hydroformylation of terminal olefins, and its commercial operation is still limited to hydroformylation of ethylene and propylene, internal olefins It has been reported in the literature that it is successfully hydroformylated by using a rhodium catalyst. Therefore, by using a rhodium catalyst, internal olefins are reported to react faster than terminal olefins. [H.Wakamatsu: NippoN kagaku Zasshi: 85, (3), 227-231 (1964): Chem. Abs., 61,13173 (1964).

An experimental process of hydroformylation of butene using a rodum catalyst is shown in Japanese Patent Publication No. 575/66 (Japanese Patent Application No. 12,124 / 63). It is reported that iso-valeraldehyde (? -Methylbutyraldehyde) can be prepared by hydroformylation of butene-2 at a temperature not higher than 80 ° C. using rhodium carbonyl as a catalyst. Of optically active 2-methylbutyraldehyde (iso-valeraldehyde) by hydroformylation of butene-1 and butene-2 using chloro-dicarbonyldium dimer and optically active diphosphine as co-catalyst The preparation is described in Japanese Unexamined Patent Publication No. 52 / 057,108. Hydroformylation of butene-1 using RhH (Co) (PPh ₃ ) ₃ as catalyst and P (OPh) ₃ as co-catalyst is described in Japanese Patent Publication Nos. 73 / 40,326 and 73 / 43,799 It is.

A method for producing a mixture of n- and iso-valeraldehyde by hydroformylation of butene-1 in the presence of a rhodium catalyst is disclosed (German Patent No. 953,605), and hydroformylation of iso-butylene is also described. Described. (See J. E. knap. N. R. Cox and W. R. Privette, Chem, Eng. Progr. 62, No. 4, 74 (1966)).

Also using an rhodium catalyst such as hydridocarbonyltris (triphenylphosphine) rhodium (I), auto-pyrolysis of petroleum containing 5-30% ethylene, 1-10% propylene and up to 5% butylene There has been a proposal to prepare a mixture of C ₃ -C ₅ aldehydes by hydroformylation of a gas formed during application. This proposal is described in French Patent Specification No. 2,249,061. Whether butene-1 is present in the ethylene-containing feed gas is not reported experimentally in detail.

Example 3 of US Pat. No. 3290379 discloses butene-1, 2-methyl butene using dicobalt octacarbonyl modified with triphenylphosphite at a temperature of 125 ° C. and a pressure of 3600 kPa (24840 kPa) as a catalyst. A process for hydroformylation of a mixture of equal parts by weight of -2 and diisobutylene is described. In the above examples, an unhindered olefin compound present in an olefin mixture containing a slightly hindered olefin compound (2-methylbutene-2) and a heavily hindered olefin compound (diisobutylene) ( Selective hydroformylation of butene-1) alone is described. According to the definition of “uninterrupted olefin mixture” in column 5 columns 5-10, cis- and trans-butene-2 are each undisturbed olefin compounds, so if Example 3 herein is butene-1 and cis-and It may be hydroformylated if repeated using a C ₄ -olefin mixture containing both trans-butene-2.

U.S. Patent No. 3965192 discloses butene-1 using a complex combination of carbon monoxide and an organic ligand such as Rh (H) (CO) [(C ₆ H ₅ ) ₃ P] ₃ as a catalyst of Group VIII noble metal hydrides. And hydroformylation of C ₂ -C ₂₅ olefins containing butene-2, and the use of excess ligands containing 2-10 times the stoichiometric amount of ligands complexed with the noble metal catalyst. It is proposed. Example 3 describes several experiments used in the case of a mixture of cis- and trans-butene-2 and other iso-butylene. This document does not address how to selectively hydroformylate butene-1 in a mixture containing one or more other C ₄ -olefins.

From these published reports, the use of a mixed C ₄ -olefin feed in the rhodium contact hydroformylation process by reaction of butene-1, butene-2 and iso-butylene, respectively, results in the reaction of n-valeraldehyde, iso-valeraldehyde. It is known that a mixture of (2-methylbutyraldehyde) and 2,2-dimethylpropion aldehyde is produced. Therefore, it is considered necessary to use pure butene-1 as raw material oil in order to obtain a high ratio of n- / iso-product aldehyde.

The invention isobutyl minimizing the formation of the composition according to the alkylene and the reaction product aldehyde, as well as iso-valeric aldehyde, and 2,2-dimethyl-propionic mixed under conditions that minimize the formation of C ₄ aldehyde-olefin feed stream from n- It is an object of the present invention to provide a rhodium-contacted hydroformylation process for preparing valeraldehyde, whereby an n- / iso ratio of at least about 8: 1 is obtained.

We find that n-valeraldehyde is very good at high conversion of butene-1 by using rhodium complex catalysts, using excess triorganophosphorus ligands and carefully controlling the temperature and partial pressure of reactants and / or products. It has been found that butene-1 in the mixed C ₄ -olefin feedstream can be prepared by hydroformylation with an iso-product aldehyde ratio and low conversion of butene-1 to butane and / or butane-2.

According to the present invention, the hydroformylation method for producing n-valeraldehyde is carried out in the presence of a catalytic amount of rhodium complex catalyst (the catalyst is composed of rhodium complexed with carbon monoxide and triorganophosphine). A temperature range of about 80-130 ° C., and a carbon monoxide partial pressure of no greater than about 50 kg / cm ² (absolute) and about 1.5 kg / cm ² (absolute) and a hydrogen of about 1.0-7.5 kg / cm ² (absolute) At partial pressure, the C ₄ -olefin crude oil (which is cis-butene-2, trans-butene-2, and iso) in the hydroformylation zone in the presence of at least about 100 moles of free toric organophosphine ligand per gram atom of rhodium - consists of olefin and butene-1) in contact with the carbon monoxide and hydrogen, and then hydro-formyl illustration unreacted from the band C ₄ - - olefins and n- valeric Al least one selected from C ₄ butylene It consists in recovering the hydroxide.

Under the hydroformylation conditions of our choice, the cis and trans-butene-2 hydroformylates extremely slowly, as iso-butylene. Furthermore, the process is characterized by the absence of resin formation when the C ₄ -olefin crude oil contains iso-butylene.

Butene-1 can undergo various reactions under hydroformylation conditions. Thus, in addition to the required product of n-valeraldehyde, some butene-1 can also be converted to the corresponding iso-1aldehyde, ie iso-valeraldehyde. These aldehydes can be condensed with themselves or with other aldehydes to produce a series of dimers, trimers, tetramers and other high molecular weight products as described below. In addition, the inventors have found that isomerization of butene-1 to cis and trans-butene-2 can be in the presence of a hydroformylation catalyst. Such isomerization cannot occur as ethylene or propylene. The cis- and trans-butene-2 essentially acts as an inert in the reaction because the cis- and trans-butene-2 is hydroformylated very slowly compared to butene-1 under the hydroformylation conditions chosen by the inventors. The isomerization of butene-1 to butene-2 is therefore a corresponding reduction in the total yield of aldehyde product from butene-1. Another reaction that may occur is the reduction of butene-1 to n-butane.

Maximize the conversion of n-valeraldehyde of butene-1 in the C ₄ -olefin crude oil in commercial plants, the formation of iso-aldehydes, the conversion of butene-1 to cis- and trans-butene-2, and n Minimizing the reduction to butane is the intended purpose. We have found that this object can be achieved by the use of specified partial pressure conditions and the use of temperatures within a given range with the use of excess triorganophosphine ligands. In some experiments we have found that butene-1 can be converted to n-valeraldehyde with an n- / iso-product aldehyde ratio of at least 20: 1 and an efficiency of at least 85%.

Iso-butylene in the process of the present invention does not form a resin with the product n-valeraldehyde to a significant extent. Thus, there is no need to pickle or pretreat the crude oil to remove iso-butylene, as is required in the corresponding cobalt-contact reaction.

The method operates in the range of about 80-130 ° C. As the temperature rises, the rate of isomerization of butene-1 to butene-2 increases. In some experiments the inventors found that at about 130 ° C. or higher, about 30% of butene-1 isomerized to form butene-2, while at 110 ° C., about 5% was converted to butene-2. Such resins dropped to about 3% at 100 ° C and 1-2% at 90 ° C. It is therefore preferred to operate at temperatures of about 120 ° C or below, preferably at about 90-110 ° C. In contrast, ethylene and propylene can be successfully hydroformylized at temperatures up to 145 ° C. to produce high yields of aldehyde products and only minor byproducts.

U.S. Patent No. 3,527,809 recommends that there must be at least 2 moles of triorganophosphorus ligand per mole of rhodium, preferably at least 5 moles of free triorganophosphorus ligand per mole of rhodium. Example 76 above shows a molar ratio of rhodium to triphenylphosphine of about 55: 1 and the actual upper limit is about 100: 1 and in most cases the upper limit of about 30: 1 is of commercial interest. It is considered to be.

(See column 5, column 63 to column 6, column 4 of US Pat. No. 3,527,809). In the hydroformylation of mixed C ₄ -olefin crude oils, the inventors of the present invention best manipulated with at least about 100 moles per gram atom of rhodium, preferably at least about 150 moles to about 500 moles or more free triarylphosphine ligands. I knew that. About 1000 moles of free ligand per rhodium gram atom can be considered as the practical upper limit of manipulation.

The triorganophosphine ligand may be a trialkylphosphine, such as tributylphosphine, or an aryldialkyl-phosphine, such as alkyl-diarylphosphine or phenyl-dibutylphosphine, such as butyldiphenylphosphine. However, triorganophosphine ligands are preferably triarylphosphine ligands such as triphenylphosphine. However, tri-P-tolylphosphine, trinaphthalylphosphine, phenyldinaaprilylphosphine, diphenylnaphthylphosphine, tri- (P-methoxy-phenyl) phosphine, tri- (P-cyanophenyl) Phosphine, tri- (P-nitrophenyl) phosphine, PN, N-dimethylamanophenyl bisphenylphosphine and the like and the like can be used as needed. Mixtures of triorganophosphines can be used.

The total pressure is not greater than about 50 kg / cm ² (absolute), which corresponds to the total pressure of the partial pressures of the reactants and products and inert materials that may be present. Typically the total pressure is at least about 4 kg / cm ² (absolute) but not more than about 20 kg / cm ² (absolute).

The partial pressure of carbon monoxide should be about 1.5 kg / cm ² (absolute) or less, preferably about 1.0 kg / cm ² (absolute) or less.

Typically it is preferred to operate at a partial pressure of at least 0.1kg / cm ^2, such as about 0.5-1.0kg / cm ² range (absolute) carbon monoxide. It was found that the n- / iso-product aldehyde ratio was adversely affected when the partial pressure of carbon monoxide was used above about 1.0 kg / cm ² .

Another important feature is the partial pressure of hydrogen. It is preferably in the range of about 1.0-5.0 kg / cm ² (absolute), especially about 1.0-3.0 kg / cm ² (absolute). Although hydrogen partial pressures greater than 5.0 kg / cm ² (absolute) can be used without adverse effects during the reaction, the use of such high hydrogen partial pressures allows the excess of unreacted hydrogen to be released to the atmosphere in discontinuous or batch processes. This implies that large or uneconomically large purification streams should be used to prevent the formation of byproducts. In both cases, the relatively expensive loss of hydrogen means unnecessary consumption. It is usually preferred to operate at a hydrogen partial pressure of about 1.25-3.0 kg / cm ² (absolute).

The butene-1 partial pressure in the process of the invention is preferably about 4.0 kg / cm ² (absolute) or less. That typically operate in the butene-1 negative pressure of about ^{0.4kg / cm 2 -3.0kg / cm 2} ( absolute), especially from about ^{0.4kg / cm 2 -1.5kg / cm 2} ( absolute) is preferred. Although the use of higher butene-1 partial pressures does not have a significant effect on the n- / iso-product aldehyde ratio or the conversion of butene-1 to aldehydes, the use of higher partial pressures of large amounts of butene-1 There is no advantage in using butene-1 partial pressure of 4.0 kg, cm ² or more because it requires the presence and, as a result, the amount of liquid in the hydroformylation zone increases and requires the use of a large amount of reactors. Furthermore, the higher the partial pressure of butene-1, the higher the concentration of butene-1 in the gas purification stream and thus the greater the loss of butene-1.

C ₄ -olefin crude oil may be introduced in the hydroformylation zone in liquid or gaseous form, which is in addition to butene-1 at least one cis- and trans-butene-2, iso-butylene, n- and iso-butane And trace amounts of hydrocarbons such as propane and pentane. The proportion of butene-1 in the C ₄ -olefin crude oil can vary within a wide range, such as from about 10 mole% to 90 mole% or more. Typically, however, the C ₄ -olefin crude oil contains about 20 mol% -80 mol% butene-1. Such crude oils are desired to be free of catalyst poisons such as inhibitors such as butadiene, sulfur compounds and chlorine compounds. Thus mixed C ₄ -olefin crude oils are hydrofined to lower the level of these inhibitors, for example to remove butadiene and practically all catalytic poisons, such as treatment with alumina and / or zinc oxide to remove gaseous sulfur compounds. And preferred pretreatment such as treatment with copper impregnated carbon to remove gaseous chlorinated impurities. As a method C ₄ - in which desulfurization is passed through the oil olefin feed to the alumina and / or sub-image of the oxidation then is not optionally sulfur that can be passed through the hydro-formyl illustration band by distillation after dechlorination by contact with copper impregnated carbon butene- One top stream and a top bottom stream rich in cis- and trans-butene-2 are obtained. This process is described in detail in European Patent Application No. 79 / 302,707.9, filed simultaneously by the Applicant, and described herein by reference.

The material fed to the hydroformylation reaction zone (ie, C, -olefin feed and / or syngas) may contain one or more inert gas materials such as nitrogen. Moreover, the presence of a small amount of oxygen, such as about 0.1 volume%, is not detrimental to the conversion of butene-1 to the n-valeraldehyde product. In this case, however, the triorganophosphine oxide should be removed and the reaction zone supplemented with a corresponding amount of triorganophosphine.

The aldehyde product produces a partial pressure at the reaction temperature used. Thus, the aldehyde partial pressure may be about 0.2-1.0 kg / cm ² (absolute) or higher. Typically about 0.5-0.8 kg / cm ² (absolute).

The catalyst used in the process of the invention is a rhodium complex catalyst composed of rhodium complexed with carbon monoxide and triorganophosphine ligands. The catalyst is preferably free of halogen such as chlorine and contains hydrogen, carbon monoxide and triorganophosphine complexed with rhodium.

Typically the catalyst is in solution. The solvent may contain an inert solvent such as toluene or cyclohexane in addition to the excess ligand. Alternatively, the solvent may contain a high boiling concentrated product with many hydroxyl compounds. The formation method of such a liquid concentrated product will be described later.

Under the reaction conditions used in the process, the n- and iso-aldehyde products condense with themselves or with other aldehydes to form a series of dimers, trimers and tetramers. For example, the reactions included in the self-condensation of n-valeraldehyde are shown in Table 1.

TABLE 1

Of course, the reaction shown includes only n-valeraldehyde. Similar products can be prepared by condensing n-valeraldehyde with iso-valeraldehyde and condensing the obtained aldol with either aldehyde to form the corresponding trimers and tetramers. Thus condensed organisms are complex compounds. For simplicity only the condensation products of n-valeric aldehyde itself are described below, but for example reference to aldol (B) includes not only the iso- / iso- eggs but also the corresponding mixed n-1 iso-aldol.

In Table 1 and Park Jung-Sik, the aldol (A), substituted acrolein (B), trimer (C), trimer (D), dimer (E) tetramer (F) and tetramer (G) Named for convenience. Aldol (A) is formed by aldol condensation, trimer (C) and tetramer (G) are formed via Tischenko reaction and trimer (D) is formed through trans-esterification reaction: Sieve (E) and tetramer (F) are formed by a dismutation reaction. Important condensation organisms are trimers (C), trimers (D) and tetramers (G), and small amounts of other products are believed to be present. Such condensation products thus contain considerable amounts of hydroxyl compounds, for example as evidenced by trimers (C) and (D) and tetramers (G).

From our experiments, we believe that the main condensation product, corresponding to that weight of 85% by weight of all high boiling aldehyde condensation products, consists of trimers.

The concentration of rhodium in the catalyst solution may range from about 10 weight ppm to 1,000 ppm or more. However, because rhodium is a sparse and valuable metal, it is desirable to operate at the lowest rhodium concentration that achieves a viable reaction rate. Typically rhodium concentrations range from about 50 ppm-250 ppm, such as about 100-150 ppm.

Rhodium is introduced to the reaction zone in a convenient way. For example, the rhodium salt of the organic acid can be mixed with a liquid ligand and then hydrogenated prior to introduction of the buren-1-containing crude oil and the hydrogen / carbon monoxide mixture. Alternatively, the catalyst can be prepared from carbon monoxide complexes of rhodium, such as dirodium octacarbonyl, by heating with a ligand, thereby replacing one or more carbon monoxide molecules. It is also possible to prepare active species in place during the course of the hydroformylation reaction starting with ligand and rhodium metal or starting with rhodium oxide (such as Rh203) and ligand. Also convertible (pentane-2,4-diatoato) dicarbonyl rhodium (I) into hydropylation conditions and in the presence of excess ligands, such as manifolds such as rhodium hydridocarbonyl tris (triphenylphosphine) Rhodium complexes, such as HCl, may be introduced into the reaction zone as catalyst precursors. Other suitable catalyst precursors include rhodiumcarbonyl triphenylphosphine acetylacetonate, Rh ₄ (CO) ₁₂ and Rh ₆ (CO) ₁₆ .

When using polymeric aldehyde condensation products as solvents, the ratio of aldehyde to such products in the liquid reaction mixture in the hydroformylation zone can vary within wide limits. Typically this ratio is in the range of about 1: 4-4: 1 (weight), such as about 1: 1 (weight).

The process can be carried out discontinuously or batchwise, such as in a pressurized batch reactor. Typically, however, the method is preferably operated continuously.

The method can be operated using the gas recirculation method described in German Patent No. 2,715,685. Alternatively, it can be operated according to the technique of European Patent Application No. 79 / 302,708.7 filed simultaneously with the present invention, which is described herein by reference.

According to an alternative method there is provided a process for the preparation of n-valeraldehyde which comprises: (i) a rhodium complex catalyst wherein (a) rhodium is complexed with carbon monoxide and triorganophosphine, (b) excess free triorganophosphine, at least 100 moles per rhodium gram atom, and (c) liquid R-valeraldehyde Supplying a hydroformylation zone containing a product and a liquid charge consisting of a polymeric aldehyde condensation product: (ii) a liquid C ₄ -olefin crude oil (which is cis-butene-2, trans-butene-2, and iso- One other C ₄ -olefin selected from butylene and butene-1) is fed to the hydroformylation zone: (iii) hydrogen and carbon monoxide are supplied to the hydroformylation zone: 80 ℃ temperature of -130 ℃, not more than about 50kg / cm ² (absolute) chongap about 4.0kg / cm ² (absolute), the partial pressure of butene-1 of less than about 1.5kg / cm ² (absolute) or less for carbon monoxide Partial pressure, and the fraction of hydrogen of 1.0-7.5kg / cm ² (absolute) Maintaining the pressure in the hydroformylation zone (i) recovering the liquid reaction product from the hydroformylation zone (vi) reducing the pressure of the liquid reaction product: (i) then unreacted C ₄ from the liquid reaction product. Flashing the -olefin and product n-valeraldehyde and ( _iv ) recycling little liquid reaction residue in the C ₄ -olefin and product n-valeraldehyde thus obtained to the hydroformylation zone: Condensation of the product n-valeraldehyde and unreacted C ₄ -olefin followed by (i) recycling the unreacted C ₄ -olefin to the hydroformylation zone. In this alternative method, preferred method step (vii) can be carried out in one or two steps. In the former case, the flashing process produces a vapor fraction consisting of the unreacted C ₄ -olefin and the product n-valeraldehyde, and the condensate obtained after condensation of the mixture can be distilled in the distillation zone from which the bottom product composed of n-valeraldehyde is derived. The top fraction consisting of unreacted C ₄ -olefins, on the other hand, is preliminarily condensed to recycle to the hydroformylation zone. In the latter case flashing in a first stage the unreacted C ₄ - to generate a first gaseous fraction comprising olefin, and the unreacted C ₄ - olefins are thereby pre-condensation in order then to recycle the hydro-formyl illustration. In the second step, flashing, on the other hand, produces a second vapor phase fraction containing the product n-valeraldehyde and the n-valeraldehyde is then subjected to a top refinery consisting of C ₄ -olefins and a liquid columnar product containing n-valeraldehyde. Condensed and distilled in the distillation zone to obtain, the C ₄ -olefins can be pre-condensed in order to also recycle to the hydroformylation zone.

In such a method it is preferred to purify a portion of the C ₄ -olefin condensate from the system. In this way deposition of unreacted cis- and trans-butene-2 and iso-butylene is avoided. It is also desirable to remove the gaseous purification stream from the hydroformylation zone to the top of the column to prevent the deposition of inert gases such as nitrogen therein. The gas phase purge stream may also be removed from the n-valeraldehyde distillation zone and / or the C ₄ -olefin condensation zone.

By reducing the pressure at and below the reaction temperature in step (iii) and then adjusting the flashing in step (vii), it is possible to ensure that the catalyst is not heated above the reaction temperature in carrying out the process. In this way the risk of inactivation of the catalyst and the risk of isomerization of butene-1 to cis- or trans-butene-2 are minimized.

It is also desirable to purify at least a portion of the unreacted C ₄ -olefins to prevent the deposition of cis- and trans-butene-2 and the deposition of iso-butylene in the system. Such clarification streams contain much less butene-1 than the C ₄ -olefin crude oil because it converts most of the n-valeraldehyde and is rich in cis- and trans-butene-2 and iso-butylene. This clarification stream is valuable as a crude oil for producing butyrate petroleum and can be distilled, for example, to obtain butene-2 and iso-butylene streams.

The inventors have found that by appropriately selecting the reaction conditions, the n- / iso-product aldehyde ratio can be achieved at 20: 1 or more. In this case, if the aldehyde product is to be used for the preparation of plasticizer alcohols, no further distillation step is necessary to separate the n-aldehyde from iso-aldehyde. The C ₁₀ -plasticizer alcohol, consisting mainly of 2-propylheptanol, can thus be prepared by conventional aldolization, dehydration and reduction without the need to purify the intermediate product aldehyde.

The invention can be described in detail with reference to the accompanying drawings, which are schematic flowcharts of a butene hydroformylation plant and variants thereof. In the figure, the liquid C ₄ -olefin feedstream passes through the conduit 1 to the pretreatment zone 2, which passes through a continuous phase of activated alumina and zinc oxide to light sulfur impurities such as carbonylsulfide, hydrogen sulfide and methyl mercaptan. This removal is followed by removal of chlorinated impurities such as HCI by continuously passing a phase of copper-impregnated carbon (Girdler G 32 J catalyst, available from Girdler Chemicals Inc., Louisville, Kentucky, USA). The COS present by passing through the phase of the active alumina is hydrolyzed to H2S due to the traces of water present in the feedstream and the active alumina phase also partially removes H ₂ S and CH ₃ SH. The zinc oxide phase then removes the remaining H ₂ S and CH ₃ SH.

The pretreated liquid butene crude oil passes through conduit 3 to hydroformylation reactor 5 via conduit 4.

Synthetic gas purification zone where 1: 1 (capacity) H ₂ : CO syngas from a partial oxidation plant (not shown) is treated to remove metal carbonyl, sulfur impurity and chlorinated impurity via conduit (6) Supplied to (7). The syngas purified from the purification zone 7 is fed to the reactor 5 via a conduit 8.

The reactor 5 has a liquid reaction medium containing a catalytic amount of rhodium complex catalyst composed of carbon monoxide dissolved in a liquid phase composed of butene and a polymer aldehyde condensation product, and a dodium complex complexed with triphenylphosphine in addition to the product n-valeraldehyde. . It is believed that the main component of such polymer aldehyde condensation products contains trimers of the general formulas (C) and (D). The type of catalyst is believed to be hydridocarbonyltris (triphenylphosphine) rhodium (I) with the general formula HCORh (PPh ₃ ) _3, namely (2,4-pentane-dioneato) dicarbonylrhodium (I), ie A suitable catalyst precursor such as rhodium dicarbonyl complex formed with acetylacetone, or rhodiumcarbonyltriphenylphosphine acetylacetonate can be obtained in place during the hydroformylation reaction. Description of such hydroformylation catalysts is described, for example, in US Pat. No. 3,527,806. The use of aldehyde condensation products as solvents for rhodium complex catalysts is described in British Tücher Specification No. 1,338,237. In addition to the rhodium complex catalyst, the liquid phase in the hydroformylation reactor 5 also contains excess triphenylphosphine. The molar ratio of triphenylphosphine to rhodium is about 375: 1.

The temperature of the reactor 5 is maintained at 110 ° C. by circulating suitable cooling water or steam through the coil 9.

The liquid reaction medium is continuously removed from the reactor (5) via conduit (10) and passes through the relief valve (11) and conduit (12) to the combustor (13), which is caused by steam passing through the conduit (14). The medium passes through the flash drum 16 via conduit 15. The vaporous overhead product passes through demister 17, passes through conduit 18 and exits drum 16 and cools. Go to 19. The coolant is circulated from the chiller 20 through the conduit 21 to condense the butenes and product n-valeraldehyde The condensate from the cooler 19 passes through the conduit 22 and the product separator. (23), from which the overhead gas phase stream passes through conduit 24 to the gas outlet, where the condensate is pumped by distillation column containing 15 trays through conduit 25 ( 27) The top product, which mainly consists of mixed burene, The top of tower 27 is removed via conduit 28 and condensed in condenser 29 to which cooling water is supplied via conduit 30. The resulting condensate is exhaust conduit 33 via conduit 31. Go to reflux drum (32).

Liquid condensate is removed from the reflux drum 32 via conduit 34 by pump 35. Some of the condensate returns to column 27 through conduit 36 and the residue passes through conduit 37. The condensate is recycled to the reactor (5) via conduits (38) and (4), while the purge liquid is removed via conduit (39).

The liquid from the flash drum 17 is recycled to the reactor 5 through the conduit 40 by the pump 41.

The reactor 5 is equipped with a top feed conduit 42 leading to a demister 43. Condensate in demister 43 returns to reactor 5 via conduit 44. The steam discharged from the demister 43 goes through the conduit 45 to the condenser 46 through which the coolant is supplied through the conduit 47. The condensate is separated in separator 46 and returned to reactor 5 through conduit 49. Purified gas is removed through conduit 50.

The bottoms product, which consists mainly of n-valeraldehyde and also contains a small amount of iso-valeraldehyde, is recovered from the tower 27 through the conduit 51. Some of this columnar product passes through conduits 52 for purification (eg redistillation) and / or future processing and / or storage. Residue of this tower bottom product is recycled to the tower 27 through the conduit 53, the after-boiler 54 and the conduit 55. Backboiler 54 is heated by steam supplied through conduit 56.

The bleed stream is removed through conduit 57 and passed to regeneration zone 58 to prevent heavy deposits in solution in hydroformylation reactor 5. Heavy materials such as valeric tetramer and triphenylphosphineoxside, which are considered to be general formulas (F) and (G), are removed by conduit 59. The regenerated solution is recycled to the hydroformylation reactor 5 via conduit 60.

If necessary, the heavy material removing zone 58 may be omitted. Instead, the reactor consumption solution can be removed from the reactor (5) via conduit (57) and sent to the reservoir, with a removal rate sufficient to prevent heavy deposits in the reactor (5). At the same time fresh catalyst or catalyst precursor is added through conduit 60 at a rate sufficient to maintain rhodium concentration at approximately selected levels. This new catalyst can be dissolved in a suitable amount of liquid aldehyde product with the corresponding amount of free triphenylphosphine. The stored spent catalyst solution can be treated for recovery of triphenylphosphine and rhodium from which new catalyst or catalyst precursor can be prepared.

A typical method of removing heavy material in zone 58 contains phosphoric acid or at least about 40% by weight, preferably about 60% by weight, of orthophosphoric acid in a conventional mixer-precipitator after cooling to room temperature and lowering atmospheric pressure. Extracting the bleed stream in conduit 57 with an aqueous solution of phosphoric acid. Phosphate extracts containing essentially all the active rhodium catalyst and free triphenylphosphine are neutralized in the presence of a suitable organic hydrophilic solvent such as n-valeraldehyde trimer, and then the organic phase obtained is dried through conduit (60) via reactor (5). Recycle).

Alternatively, the organic residue from the phosphate extraction step is sent to the storage room via conduit 59. This organic residue contains not only high boiling n-valeraldehyde condensation products but also catalytically inert rhodium and triphenylphosphine oxides.

The composition (mol%), flow rate, temperature and pressure in various critical conduits in the plant are as described in Table 2 below. The flow rate of the conduit 35 corresponds to 221.15 kg mol / hr, while the flow rate of the conduit 36 corresponds to 117.30 kg mol / hr.

TABLE 2

The liquid reaction medium of conduit 12 to the plant described above is heated in heater 13 sufficient to flash off unreacted medium and product n-valeraldehyde. In a variant of the plant a two stage flash process is used. In such a variant of the plant, which is shown in broken lines in the figure, the liquid reaction medium of the conduit 12 is heated sufficiently by the heater 13 to flash off the butenes. Instead of refining the conduit 15 and passing it directly to the flash drum 16, a replacement is sent from the heater 13 to the separator 62 via the conduit 61. Butene is extracted from the column top via conduit 63 and sent by conduit 65 to cooler 64 to which coolant is supplied from chiller 20. The condensed butenes are recycled to the reactor 5 via conduits 66 via conduit 66 and via conduits 68, 38, and 4 while uncondensed gas passes through conduit 69. Is exhausted. The liquid from separator 62 passes through conduit 70 and through another heater 71 through which steam is supplied through conduit 72 and then to flash drum 16 via conduit 15. The size of the distillation column 27 in such a modified type of plant can be reduced compared to the size of the plant described earlier because it handles a small amount of output.

Hereinafter, the present invention will be described in detail with reference to Examples.

EXAMPLE

Hydroformylation of the C ₄ -olefin feed gas was carried out in a solution containing the product n-valeraldehyde and aldehyde condensation product in addition to the rhodium catalyst and excess triphenylphosphine. The reaction was carried out in a 2000 ml autoplate equipped with a magnetically coupled stirrer and a C ₄ -olefin feed and a Co / H ₂ mixture with a separate sparge tube. This facility is for the recovery of overhead gaseous products and its pressure can be continuously monitored. The temperature of the autoclave was precisely controlled to within ± 0.1 ° C by combining electric heating and air cooling devices using the internal air cooling coil rate. The gas feed to the autoclave was preheated by passing through a tube coil immersed in a salt bath. The CO / H ₂ mixture was prepared by mixing the gas upstream from the autoclave, and the CO / H ₂ ratio was adjusted by adjusting the valve on the gas cylinder.

The autoclave contains 300 ml of Filmer 351, "trimer" of iso-butyraldehyde, 130 g of triphenylphosphine (TPP) and 0.137 g of rhodiumcarbonyl triphenylphosphine acetylacetonate form as catalyst precursor. Charged with rhodium. The autoclave was heated to 110 ° C. and the total gas flow rate (olefin + synthesis gas) was adjusted to 600 l / hr. In each example the CO partial pressure was 0.7 kg / cm ² (absolute). The H ₂ partial pressure was 2.8 kg / cm ² (absolute). The aldehyde product was discharged from the autoclave and then collected in a water-cooled knock-out pot.

The liquid level of the autoclave is kept constant by pumping the aldehyde product back from the rust-out pot. Gas chromatography analyzes the product collected in the rust-out pot and the uncondensed gas is analyzed to control the n- / iso-product aldehyde ratio.

The CO / H ₂ mixture (synthesis gas) was purified through a bed of alumina and zinc oxide lying in series, held at 180-200 ° C. and then at 180-200 ° C. on copper-impregnated carbon. . The C ₄ -olefin feed was free of butadiene in private and was similarly purified. The results are shown in Table 3.

TABLE 3

Note: n-VAL = n-valeraldehyde

3-Me-n-BAL = 3-methyl-n-butyaldehyde, ie the product from hydroformylation of iso-butylene

Claims (1)

C ₄ -olefin crude oil in a hydroformylation zone at elevated pressure and elevated temperature in the presence of a rhodium complex catalyst containing rhodium complexed with carbon monoxide and triorganophosphine ligands and a free triorganophosphine ligand. In the process of contacting carbon monoxide with hydrogen and then recovering n-valeraldehyde from the hydroformylation zone, the C ₄ -olefin crude oil is selected from cis-butene-2, trans-butene-2 and iso-butylene. And at least one C ₄ -olefin and butene-1. In the presence of more than 100 moles of free triorganophosphine ligands per gram atom of rhodium, the hydroport milling zone is maintained at a temperature in the range of 80-130 ° C. with a total pressure of 50 kg / cm ² (absolute) and a partial pressure of carbon monoxide 1.5 kg / cm ² (absolute) or less, hydro formate way wheat illustration for the production of n- valeric aldehyde, characterized maintained by the hydrogen partial pressure is 1.0-7.5kg / cm ² (absolute).

Images